The present invention relates to a method for producing styrene by catalytic dehydrogenation of ethylbenzene, the first stage of the steam is used for heating reactant effluent, then it is used as diluting agent of ethylbenzene. Said invented method is aimed at mainly resolving the problem of that in the existent production method the excessive change of catalyst bed layer temperature in the heat-insulating bed reactor along the flowing direction of the reaction medium can affect the catalyst performance, reaction conversion rate and reaction yield. Said invention adopts the technical scheme of adding at least one heating pipe in reactor bed layer of fixed bed so as to better resolve said problem.